2 * Copyright (C) 2009 Andre Noll <maan@systemlinux.org>
4 * Licensed under the GPL v2. For licencing details see COPYING.
7 /** \file fecdec_filter.c A filter fec-decodes an audio stream. */
19 #include "portable_io.h"
24 * How many FEC groups to store in memory.
26 * Packet reordering requires to keep more than one FEC group in memory because
27 * slices belonging to the next FEC group may arrive before the current FEC group
30 #define NUM_FEC_GROUPS 3
32 /** Default size of the output buffer of the fecdec filter. */
33 #define FECDEC_DEFAULT_OUTBUF_SIZE (3 * 1024)
34 /** Maximal size of the output buffer of the fecdec filter. */
35 #define FECDEC_MAX_OUTBUF_SIZE (1024 * 1024)
37 /** Data read from the header of a slice. */
39 /** Total number of slices in this group. */
40 uint8_t slices_per_group;
41 /** Number of slices needed to start decoding. */
42 uint8_t data_slices_per_group;
43 /** Size of the ogg vorbis header (zero for mp3, aac). */
44 uint32_t audio_header_size;
45 /** Number of the FEC group this slice belongs to. */
47 /** Size of the data in this FEC group. */
49 /** Number of this slice in the group. */
51 /** Used data bytes of this slice. */
53 /** Non-zero if this group is the beginning of the stream. */
55 /** Non-zero if this stream embedds audio headers into fec groups. */
56 uint8_t header_stream;
60 * The status of one partially received FEC group.
63 /** The header read from the last slice. */
65 /** How many slices received so far. */
66 int num_received_slices;
67 /** The size of the \a idx and the \a data arrays below. */
69 /** Array of indices of the received slices. */
71 /** Content of the received slices. */
76 * Data private to the fecdec filter.
78 struct private_fecdec_data {
79 /** Used by the fec core code. */
80 struct fec_parms *fec;
81 /** Keeps track of what was received so far. */
82 struct fecdec_group groups[NUM_FEC_GROUPS];
83 /** Whether an audio file header was already received. */
87 /** Iterate over all fecdec groups. */
88 #define FOR_EACH_FECDEC_GROUP(g, d) for (g = (d)->groups; \
89 (g) - (d)->groups < NUM_FEC_GROUPS; (g)++)
91 static int group_complete(struct fecdec_group *fg)
93 return fg->num_received_slices >= fg->h.data_slices_per_group;
96 static int group_empty(struct fecdec_group *fg)
98 return fg->num_received_slices == 0;
101 static void clear_group(struct fecdec_group *fg)
105 for (i = 0; i < fg->num_slices; i++) {
113 memset(&fg->h, 0, sizeof(struct fec_header));
114 fg->num_received_slices = 0;
117 static int find_group(struct fec_header *h,
118 struct private_fecdec_data *pfd, struct fecdec_group **result)
120 struct fecdec_group *fg;
122 FOR_EACH_FECDEC_GROUP(fg, pfd) {
123 if (fg->h.group_num != h->group_num)
125 if (fg->num_received_slices == 0)
127 if (fg->h.slices_per_group != h->slices_per_group)
128 return -E_BAD_FEC_HEADER;
129 if (fg->h.data_slices_per_group != h->data_slices_per_group)
130 return -E_BAD_FEC_HEADER;
131 if (fg->h.group_bytes != h->group_bytes)
132 return -E_BAD_FEC_HEADER;
140 static struct fecdec_group *find_unused_group(struct private_fecdec_data *pfd)
142 struct fecdec_group *fg;
144 FOR_EACH_FECDEC_GROUP(fg, pfd) {
145 if (fg->num_received_slices == 0)
151 static struct fecdec_group *try_to_free_group(struct private_fecdec_data *pfd)
153 struct fecdec_group *fg;
155 FOR_EACH_FECDEC_GROUP(fg, pfd) {
156 if (!group_complete(fg))
164 static struct fecdec_group *free_oldest_group(struct private_fecdec_data *pfd)
166 struct fecdec_group *fg, *oldest = NULL;
168 FOR_EACH_FECDEC_GROUP(fg, pfd) {
169 if (!oldest || oldest->h.group_num > fg->h.group_num)
172 if (!group_complete(oldest) && !group_empty(oldest))
173 PARA_WARNING_LOG("Clearing incomplete group %d "
174 "(contains %d slices)\n", oldest->h.group_num,
175 oldest->num_received_slices);
180 /* returns 1 if the group was found, 0 if not, negative on errors */
181 static int get_group(struct fec_header *h, struct private_fecdec_data *pfd,
182 struct fecdec_group **result)
184 struct fecdec_group *fg;
185 int ret = find_group(h, pfd, &fg);
189 if (ret > 0) /* found group */
191 /* group not found */
192 fg = find_unused_group(pfd);
195 fg = try_to_free_group(pfd);
198 fg = free_oldest_group(pfd);
207 * returns 1 if slice was added, zero otherwise (because the group was already
208 * complete). In any case the number of received slices is being increased by
211 static int add_slice(char *buf, struct fecdec_group *fg)
215 if (group_complete(fg)) {
216 PARA_DEBUG_LOG("group complete, ignoring slice %d\n",
218 fg->num_received_slices++;
221 slice_num = fg->h.slice_num;
222 if (fg->num_slices == 0) {
223 fg->num_slices = fg->h.slices_per_group;
224 fg->idx = malloc(fg->num_slices * sizeof(int));
225 fg->data = malloc(fg->num_slices * sizeof(unsigned char *));
226 memset(fg->data, 0, fg->num_slices * sizeof(unsigned char *));
228 r = fg->num_received_slices;
229 fg->idx[r] = slice_num;
230 fg->data[r] = malloc(fg->h.slice_bytes);
231 memcpy(fg->data[r], buf, fg->h.slice_bytes);
232 fg->num_received_slices++;
236 enum fec_group_usability {
239 FEC_GROUP_USABLE_SKIP_HEADER,
242 static enum fec_group_usability group_is_usable(struct fecdec_group *fg,
243 struct private_fecdec_data *pfd)
245 struct fec_header *h = &fg->h;
247 if (!h->header_stream)
248 return FEC_GROUP_USABLE;
249 if (pfd->have_header) {
250 if (h->audio_header_size)
251 return FEC_GROUP_USABLE_SKIP_HEADER;
252 return FEC_GROUP_USABLE;
255 return FEC_GROUP_USABLE;
256 if (fg->h.audio_header_size)
257 return FEC_GROUP_USABLE;
258 return FEC_GROUP_UNUSABLE;
261 static int decode_group(struct fecdec_group *fg, struct filter_node *fn)
263 int i, ret, sb = fg->h.slice_bytes;
264 size_t written = 0, need;
265 struct private_fecdec_data *pfd = fn->private_data;
266 enum fec_group_usability u = group_is_usable(fg, pfd);
268 if (u == FEC_GROUP_UNUSABLE) {
269 PARA_INFO_LOG("dropping unusable group %d\n", fg->h.group_num);
272 PARA_DEBUG_LOG("decoding group %d %d slices\n", fg->h.group_num,
273 fg->h.data_slices_per_group);
274 ret = fec_decode(pfd->fec, fg->data, fg->idx, sb);
277 pfd->have_header = 1;
279 if (u == FEC_GROUP_USABLE_SKIP_HEADER) {
280 i = ROUND_UP(fg->h.audio_header_size, fg->h.slice_bytes)
282 PARA_DEBUG_LOG("skipping %d header slices\n", i);
284 PARA_DEBUG_LOG("writing group %d (%d/%d decoded data bytes)\n",
285 fg->h.group_num, fg->h.group_bytes,
286 fg->h.data_slices_per_group * sb);
287 need = fn->loaded + (fg->h.data_slices_per_group - i)* sb;
288 if (need > fn->bufsize) {
289 fn->bufsize = PARA_MAX(fn->bufsize * 2, need);
290 if (fn->bufsize > FECDEC_MAX_OUTBUF_SIZE)
291 return -E_FECDEC_OVERRUN;
292 PARA_INFO_LOG("increasing fec buf to %zu\n", fn->bufsize);
293 fn->buf = para_realloc(fn->buf, fn->bufsize);
295 for (; i < fg->h.data_slices_per_group; i++) {
297 if (n + written > fg->h.group_bytes)
298 n = fg->h.group_bytes - written;
299 memcpy(fn->buf + fn->loaded, fg->data[i], n);
307 * Read a fec header from a buffer.
309 * \param buf The buffer to write to.
310 * \param h The fec header to write.
312 static int read_fec_header(char *buf, size_t len, struct fec_header *h)
316 if (len < FEC_HEADER_SIZE)
318 magic = read_u32(buf);
319 if (magic != FEC_MAGIC)
320 return -E_BAD_FEC_HEADER;
321 h->slices_per_group = read_u8(buf + 4);
322 h->data_slices_per_group = read_u8(buf + 5);
323 h->audio_header_size = read_u32(buf + 6);
325 h->group_num = read_u32(buf + 10);
326 h->group_bytes = read_u32(buf + 14);
328 h->slice_num = read_u8(buf + 18);
329 h->slice_bytes = read_u16(buf + 20);
330 h->bos = read_u8(buf + 22);
331 h->header_stream = read_u8(buf + 23);
332 if (!memcmp(buf, FEC_EOF_PACKET, FEC_EOF_PACKET_LEN))
333 return -E_FECDEC_EOF;
334 // PARA_DEBUG_LOG("group %u, slize %u, slices per group: %u\n",
335 // h->group_num, h->slice_num, h->slices_per_group);
339 /* returns 1 if we used the buffer, 0 if we didn't, negative on errors */
340 static int dispatch_slice(char *buf, size_t len, struct fec_header *h,
341 struct filter_node *fn)
343 struct fecdec_group *fg;
345 struct private_fecdec_data *pfd = fn->private_data;
347 if (h->slice_bytes > len) /* can not use the thing, try to read more */
349 ret = get_group(h, pfd, &fg);
352 if (!add_slice(buf, fg))
354 if (group_complete(fg)) {
356 int k = h->data_slices_per_group, n = h->slices_per_group;
357 PARA_NOTICE_LOG("init fec (%d, %d)\n", k, n);
358 ret = fec_new(k, n, &pfd->fec);
362 ret = decode_group(fg, fn);
369 static ssize_t fecdec(char *buf, size_t len, struct filter_node *fn)
374 ret = read_fec_header(buf, len, &h);
378 return -E_BAD_SLICE_SIZE;
379 if (h.slice_num > h.slices_per_group)
380 return -E_BAD_SLICE_NUM;
381 ret = dispatch_slice(buf + FEC_HEADER_SIZE, len - FEC_HEADER_SIZE,
383 //PARA_INFO_LOG("ret: %d, len: %d, slice_bytes: %d\n", ret, len, h.slice_bytes);
386 return FEC_HEADER_SIZE + h.slice_bytes;
389 static void fecdec_close(struct filter_node *fn)
391 struct private_fecdec_data *pfd = fn->private_data;
392 struct fecdec_group *fg;
394 FOR_EACH_FECDEC_GROUP(fg, pfd)
399 free(fn->private_data);
400 fn->private_data = NULL;
403 static void fecdec_open(struct filter_node *fn)
405 fn->bufsize = FECDEC_DEFAULT_OUTBUF_SIZE;
406 fn->buf = para_malloc(fn->bufsize);
407 fn->private_data = para_calloc(sizeof(struct private_fecdec_data));
412 * The init function of the fecdec filter.
414 * \param f struct to initialize.
416 void fecdec_filter_init(struct filter *f)
419 f->close = fecdec_close;
420 f->open = fecdec_open;